Q2d. Manually calculate the difference score "D" by subtracting each "Age 75" memory score from the associated "Age 85" memory score for each subject. Fill in the column in the table below for "difference score."

[1 point total: deduct 0.5 for each error up to 1 point.]

Hint: The difference score is calculated as (age 85 minus age 75), so a negative number indicates a decline in memory performance, which is the researcher's hypothesis.

Subject	Difference score "D" (Age 85 - Age 75)
1	-7
2	-6
3	-4
4	-2
5	-2
6	-5
7	-3
8	0
9	-2
10	-2

Q2e. Manual calculation: Calculate the mean from the sample of difference scores. Round the result to the hundredth (2^nd place to the right of the decimal).

[1 point: 0.5 if process is correct but answer is wrong]

Answer: Mean is -3.30 Adding all scores and dividing them by 10

Q2f. Manual calculation: Estimate the standard deviation of the population of difference scores (use N-1). Round the result to the hundredth (2^nd place to the right of the decimal).

[1 point: 0.5 if process is correct but answer is wrong]

Answer: Standard Deviation is 2.16

Q2g. Manual calculation: Calculate the standard error (standard deviation of the sampling distribution). Round the result to the hundredth (2^nd place to the right of the decimal).

[1 point: 0.5 if process is correct but answer is wrong]

Answer: 0.68

Q2h. Manual calculation: Calculate the paired-samples t statistic for the sample of difference scores. Round the result to the thousandth (3^rd place to the right of the decimal).

[1 point: 0.5 if process is correct but answer is wrong]